The Universal Mobile Telecommunication System (UMTS) is one of the third generation mobile communication technologies designed to succeed GSM. 3GPP Long Term Evolution (LTE) is a project within the 3rd Generation Partnership Project (3GPP) to improve the UMTS standard to cope with future requirements in terms of improved services such as higher data rates, improved efficiency, lowered costs etc. The Universal Terrestrial Radio Access Network (UTRAN) is the radio access network of a UMTS and evolved UTRAN (E-UTRAN) is the radio access network of an LTE system. In an E-UTRAN, a user equipment (UE) 150 is wirelessly connected to a radio base station (RBS) 110a-c commonly referred to as an eNodeB (eNB), as illustrated in FIG. 1a. The eNBs 110a-c are directly connected to the core network (CN) 190 via the S1 interface. In UTRAN however, the radio base stations or NodeBs (NB) are connected to the CN via a Radio Network Controller (RNC) which controls the NBs connected to it.
The trend in the evolution of wireless access technologies is a continuously increased capacity, but also higher complexity in order to meet the tougher throughput and delay requirements. Coordinated multipoint transmission/reception (COMP), where signals are simultaneously and coherently transmitted/received from/to multiple RBSs to improve performance, and multiple-input multiple-output (MIMO), where the performance is improved as both the transmitter and the receiver are equipped with multiple antennas, are two examples of elements in LTE that help reaching high throughputs. However these elements may also increase the energy consumption in the system.
The focus on sustainability and energy consumption in telecommunications systems is increasing. In 3GPP LTE technology, most energy is consumed during the phase when the eNB is in operation. Thus, methods for reducing the energy consumption for deployed eNBs are important. In prior art, the communications system strives to offer each user the best possible quality of service (QoS) within the frame of the user's subscription, and the radio resource management algorithms prioritize highest possible throughput and lowest possible delay and packet loss. This often means spending more energy than strictly necessary to transfer the data.
An environmental friendly user of e.g. an E-UTRAN may, at least in some situations or for some connections, accept a lower throughput or longer delay e.g. if that would reduce the energy consumption in the system. However, a problem in the current 3GPP standards is that there is no possibility to differentiate the trade off between energy saving and throughput, and all UEs are prioritizing throughput in the same way.